I. Field
The invention relates to a method and means of connecting devices in a Wireless Personal Area Network (WPAN) and Wireless Local Area Network (WLAN). In particular, but not exclusively, it relates to interfacing wired protocols with an IEEE 802.15.3 wireless protocol.
II. Description of the Related Art
WPANs and WLANs employing millimeter-wave communications will be used for short-range communication in home networks and between various Consumer Electronics devices. For the purposes of this disclosure, WPANs include ultra-wideband, short-range networks configured to transfer large volumes of data between personal devices and any larger networks with which those devices may interface. To facilitate such applications, an ultra-wideband network requires medium access control between a plurality of different high-data-rate devices. For example, the IEEE802.15.3 protocol may be used for peer-to-peer communication in a WPAN.
A millimeter-wave WPAN capable of providing data rates in excess of 6 Gbps for a range up to 10 m is currently being standardized in IEEE802.15.3c. A very high throughput WLAN standard for 60 GHz is also being considered under VHT60. One potential application of WPANs and WLANs is to provide wireless connectivity between peripheral devices in a computer network. For example, prior-art aspects of WPANs enable current wired protocols (USB, IEEE1394, PCIE, DVI/HDMI, SATA, 1 GbE, etc.) to be transmitted over a wireless channel. However, each of these wired protocols has very strict latency requirements and strict timing requirements between transmitting and receiving an acknowledgement message (e.g., an ACK or a NACK). Thus, an end-to-end wireless solution for peripherals employing wired protocols suffers from significant performance impediments due to latency in the wireless medium and protocol.
FIG. 1 illustrates a prior-art solution for providing wireless support to a plurality of different peripheral devices. For example, one peripheral device may have a USB interface, a second peripheral device may have a 1394 interface, a third device may have a PCIE interface, and a fourth device may have an HDMI interface. The prior-art solution provides for a protocol adaptation layer (PAL) 101-104 for each peripheral and a sub-MAC 111-114 for each peripheral. Furthermore, a wireless driver (not shown) is required on each end of each peripheral.
In a wireless system having a transmitting end and a receiving end, each end comprises a standard wired peripheral transceiver and a wireless transceiver. The transmitting end transmits a packet to the receiving end, and it sets up a timer and expects an ACK or NACK within a predetermined time (i.e., before the timer expires). However, due to latency in the wireless channel and the wireless protocol, the returned ACK or NACK often arrives too late (i.e., after the timer has expired), even if the receiving end receives the packet correctly. The transmitting end assumes that the packet is lost and takes action based on this incorrect assumption, such as retransmitting the packet and ratcheting down the transmission rate. This is only one of many issues that impede the performance of an end-to-end solution employing both wired and wireless protocols.
The WiMedia alliance addressed this issue with respect to the USB protocol. WiMedia defined a new protocol, Wireless USB (WUSB), which requires major changes to the USB MAC and provides a PAL and a new driver on each end to replace the wired existing driver. If this approach is used to provide wireless support for all the wired protocols for peripherals, it would require introducing a set of PALs for each wired protocol, reconfiguring the MAC for each peripheral, and providing a new set of wireless drivers to replace the existing wired drivers.